The invention relates to a transmission module for a differential assembly for variably distributing torque in the driveline of a motor vehicle and to a differential assembly having such a transmission module. Differential assemblies of said type commonly comprise a differential drive with one input shaft and two output shafts, wherein the output shafts have a balancing effect relative to one another.
The mode of functioning of the differential assembly for variably distributing torque is such that part of the torque introduced via the input shaft is branched off by the differential carrier prior to being distributed to the two output shafts. The branched-off part of the torque is additionally introduced into one of the two output shafts behind the region where the remaining torque is distributed. For this purpose, a transmission stage and a friction coupling are provided for each output shaft. The transmission stage comprises an input gear which is driven by the differential carrier and which is accelerated or decelerated by an output gear. The latter is accelerated or decelerated by coupling the output gear to the associated output shaft of the differential. If required, a greater amount of torque can be transmitted to the one of the two output shafts than to the other one of the output shafts in order to increase the driving stability of the motor vehicle. Such transmission assemblies can be used for distributing torque between the two sideshafts of an axle differential or for the controlled distribution of the torque between the two output shafts of a central differential of a motor vehicle driven by a plurality of axles.
From DE 10 2005 004 291 A1 there is known a differential assembly with a differential drive and two transmission stages. Each of the transmission stages comprises two sun gears with different numbers of teeth, as well as planetary gears engaging the sun gears. For the purpose of achieving a transmission ratio from the first sun gear to the second sun gear, these comprise teeth whose profiles are displaced relative to one another and which engage continuous teeth of the planetary gears.
It is the objective of the present invention to propose a transmission module for a differential assembly which has a simple design, which permits a high setting accuracy and features low power losses. Furthermore, it is the object of the present invention to propose a transmission assembly for the variable distribution of torque, having such a transmission module.